Nalgene BPA Free Tritan Narrow Mouth Water Bottle, Clear, 32 Oz For those who prefer a roomy bottle with a smaller opening, we offer our narrow-mouth loop top bottle. A top that minimizes the chance of spills. Attached cap never gets lost. Printed graduations for easy measuring. Made from Eastman Tritan copolyester that is manufactured without BPA. Resistant to staining and retaining odor.